Scaling Clearbit to 2M API Requests Per Day

5,271
Clearbit
APIs for determining who's behind an email address

By Harlow Ward, ‎Developer and Co-founder at Clearbit.


Clearbit builds Business Intelligence APIs - Our suite of APIs are focused on Lead Enrichment and Automated Research.

Clearbit lookup example

Our goal is to help modern businesses make better data-driven decisions. Our platform aggregates data from hundreds of public sources and packages it up into beautifully hand-crafted JSON payloads.

Customers use our APIs to:

  • Give their sales team more information on customers, leads, and prospects.
  • Integrate and surface person/company data to the end-users of their systems.
  • Underwrite transactions and reduce fraud.

Outside of our paid products we also love releasing free products. These bite sized APIs are hyper focused on helping designers and developers enhance the user-experience of their tools and systems.

A few of these freebies include:


Engineering at Clearbit

Our engineering team consists of three developers: Alex MacCaw (also our fearless CEO), Rob Holland, and myself.

We are a small dev team, and that means we all wear a lot of hats. Day-to-day, it’s not uncommon to jump between Frontend HTML/JS/CSS, API design, Service administration, DB administration, Infrastructure management, and of course a little customer support.


Services Everywhere

We made the decision early on to build a microservice-first architecture. This means our system is composed of lots of tiny Single Responsibility Services (SRS anyone?).

In general these services are written in Ruby, leverage Sinatra to expose JSON endpoints, and use RSpec to verify accuracy. Each service maintains its own datastore; depending on the service's needs we’ll typically choose from Amazon RDS, Amazon DynamoDB, or hosted Elasticsearch with Found.

There are some great arguments to be made about a MonolithFirst architecture. However, in our case, we felt our data boundaries were reasonably clear from the beginning, and this allowed us to make a few low-risk bets around building and running a microservice-first architecture. So far so good!

Our web services fall into two categories:

  1. External (publicly accessible, authenticated via API keys).
  2. Internal (accessible within VPC, locked down to specific security groups).

At any given time we’re running 70+ different internal services across a cluster of 18 machines. Our external (customer facing) APIs are serving upwards of 2 million requests per-day, and that number is rapidly increasing.


Early Days

When working with a microservice architecture it's difficult to overstate how important it is for a developer to be able to quickly push a new web service.

Our initial aritecture was built on Amazon EC2 and leveraged dokku-alt (a Docker powered mini-Heroku) to manage deployments.

Dokku-alt covered our basic requirements:

  • Git based deploys.
  • Managing ENV vars outside of config files.
  • Ability to rollback in case of emergency.

However, as the number of servers grew some shortcomings of dokku-alt began to emerge. This was no fault of dokku-alt; we were just outgrowing our architecture.

As we added more machines the problems compounded. The per-machine configuration management we had initially loved quickly became unsustainable. On top of that, running git push production master simultaneously to every box in the cluster made for some nerve-racking deploys.

The state of our deployment system was beginning to take a toll on the team's productivity. It was time to make a change. We collectively decided to explore our options.


Current Stack

As our infrastructure grew, our deployment requirements also evolved:

  • Distributed configuration management.
  • Git push to only one repository.
  • Blue/Green style deploys.

After looking into solutions like Deis and Flynn, we decided we'd feel happier with something with simpler semantics. We were attracted to Fleet because of it's simplicity and flexibility, and the reputation of the CoreOS team.

Co-ordinating configuration between machines became a breeze with the use of etcd. Now when our deployer app builds a new docker container we can inject environment variables from etcd directly into the container.

From there, we use Fleet to distribute the units accross our cluster of servers. We’ve found fleet-ui super handy for visualizing the distribution of units across our cluster.


fleetui


To keep our operational expenses down, we have a static pool of on-demand EC2 instances running the etcd quorum, HAProxy, and several of the HTTP front ends. On top of that, we leverage a dynamic pool of EC2 Spot Instances to handle the dynamic nature of our workloads during times of extremely high throughput.

Word to the wise: Don’t use Spot Instances as part of your etcd quorum -- When someone else bids higher than the current Spot Price (and they will), the Spot Instances will disappear without warning.


Monitoring

It’s hard to stress how important it’s been for us to have a deep and instantly available understanding of the current state of all our services.

Starting from the outside, we use Runscope to continually ping and analyze responses from our services. It’s been instrumental in verifying and maintaining the APIs with dynamic date versioning.

Digging a level deeper, we use Librato for measuring and monitoring lower level system behaviour. We’re diligent about creating alerts that will notify the team if anything seems awry.

Sentry notifies us immediatly via Slack and Email if any of our services are throwing errors. We’re big believers in the Broken windows theory, and try to keep Sentry as clean as possible.

Finally, we use SumoLogic as our log aggregation platform. We run Sumo Collectors on each of our hosts. SumoLogic is our last line of defense for spotting inconsistent system behaviour and debugging historical issues.


Looking Forward

We have a private contrib repo with a handful of rack middlewares that are shared across our services. These middlewares dramatically cut down on duplication of code around Authentication, Authorization, Rate Limiting, and IP Restrictions.

In general, the shared middleware approach has worked well for us. However, as we look to the future and the team continues to experiment with new languages, the Ruby middlewares can’t be shared across new languages in the polyglot system.

Our goal is to push this shared logic out of the services and into the proxy layer (possibly with the help of VulcanD, Kong, or some custom HAProxy foo).

If you have made a transition like this before, or have a an elegant idea of how to summersault this hurdle, I’d love to buy you a beverage. harlow@clearbit.com


Clearbit
APIs for determining who's behind an email address
Tools mentioned in article
Open jobs at Clearbit
Customer Success Engineer
San Francisco Bay Area
We are looking to add a foundational member to our Customer Success Engineering team - someone who loves delighting customers as much as they like influencing product and finds excitement in being a large part of building a cross-functional team from the ground up. Clearbit is a rapidly growing SaaS company (> 250% ARR last year) looking for talented and experienced B2B customer success folks to take us to the next level. We've been profitable since year 1, after raising a small seed round from FirstRound, SV Angel, and Zetta. We often compete (and win) against companies 10x our size, and we're looking to grow rapidly over the next year. If you're looking for a highly collaborative environment with a very experienced team working on awesome cutting edge products, Clearbit is the place. You’ll be one of the first hires in this role, so it comes with a tremendous level of ownership. Check out our Glassdoor Reviews
  • Become an expert in our products (Salesforce and API based solutions)
  • Work with a diverse customer base on an ongoing basis, implementing, troubleshooting (sometimes in real time) and filing bugs as they arise, consulting customers of solutions and best practices along the way
  • Support the Customer Success Management team in deal renewals, cross-sells, etc.
  • Review and document our solutions are integrated as expected before handing the case back to Customer Success Manager team
  • Scope out and potentially build new integrations
  • Support Sales via sales engineering responsibilities as needed
  • Document and build internal tools/apps to help customer success, sales, and other teams as needed
  • 1 to 3 years of Sales Engineering, Solution Architecture/Engineering, or Success Engineering (or equivalent) experience in B2B SaaS
  • Problem-solving ability, customer centric outlook and excellent communication skill
  • Experience working with cross-functional teams (Sales, Marketing, Product)
  • Working knowledge of either Javascript or Salesforce, with the ability and interest to continue expanding on that working knowledge
  • Ability to work out of our San Francisco HQ
  • Highly Preferred: Experience working with SQL, Javascript, and APIs
  • Bonus Points if you're familiar with industry standard marketing and sales solutions - Google Analytics, Adobe Analytics, Optimizely, Marketo, Pardot, Hubspot, Eloqua, etc, have completed Salesforce Trailhead training, or are familiar with SOQL
  • Senior Full Stack Engineer, X
    San Francisco, CA (or Remote US)
    Who We Are Clearbit is the marketing data engine for customer interactions. We help businesses grow by providing tools that help them deeply understand their customers, identify future prospects, and highly personalize every single marketing and sales interaction. What You'll Do As a Full Stack engineer on the X team, you'll be integral in the design and development of one of our new core products. You'll be working very closely with the rest of our team, building and maintaining a rich, easy-to-use control plane for modern marketing workflows. We value ownership and knowing what questions to ask very highly—the ability to take an idea through all the stages from conception to shipping a product. This reflects throughout our company, but is especially true in engineering. As an engineer at Clearbit, you'll be highly independent and autonomous. Since we're building such disparate data APIs and products you'll be working with a large array of different technologies and fields. Expect lots of interesting challenges.
  • Work with a Ruby/Sinatra/Sequel/Postgres stack on the backend
  • Work with HTML/CSS/JS/React on the front end
  • Bring new features from concept to shipped product
  • Come up with new product directions and contribute with ideas
  • 4+ years of development experience
  • 2+ years of experience in Ruby
  • 2+ years of experience with React preferred
  • Independent and self motivated—maintaining side projects and libraries a major plus
  • San Francisco, CA or remote in US timezones
  • A brief write-up explaining who you are as a programmer. For example, how you got started, what area of the stack you feel most familiar with, what motivates you, what technologies you want to learn over the next year
  • Some ways you think Clearbit could improve, APIs we could add etc
  • A side project you really enjoyed working on
  • Links to online profiles you use (GitHub, Twitter, etc)
  • A description of your work history (whether as a resume, LinkedIn profile, or prose)
  • Support Engineer
    San Francisco, CA (or Remote, US Timezones)
    We are looking to add a foundational member to our Support Engineering team - someone who loves delighting customers as much as they like influencing product and finds excitement in being a part of building a cross-functional team from the ground up. Clearbit is a rapidly growing SaaS company (> 250% ARR last year) looking for talented and experienced B2B customer success folks to take us to the next level. We've been profitable since year 1, after raising a small seed round from FirstRound, SV Angel, and Zetta. We often compete (and win) against companies 10x our size, and we're looking to grow rapidly over the next year. We offer a highly collaborative environment with a very experienced team working on awesome cutting edge products. You’ll be one of the first hires in this role, so it comes with a tremendous level of ownership and growth potential. If you enjoy cross-functionality, learning about MarTech and SalesTech, understanding customer challenges, working with the hottest startups and large enterprise companies, developing deep understandings about products, and being a true consultant for best practices, this is your role! Check out our Glassdoor Reviews
  • Become an expert in our products
  • Work with a diverse customer base on an ongoing basis, guiding, troubleshooting (sometimes in real time) and filing bugs as they arise, consulting customers of solutions and best practices along the way
  • Be the first point of escalation for our customers
  • Review and document integrations in production
  • 1 year experience in B2B SaaS Support
  • Understanding of basic website development (html, css, js)
  • Experience working directly with customers and is driven by delivering exceptional customer experience
  • Comfortable in ambiguity and self sufficient in trying to find the solution
  • Problem-solving ability, customer centric outlook and excellent communication skill
  • Experience working with cross-functional teams (Sales, Marketing, Product)
  • Bonus Points if you're familiar with industry standard marketing and sales solutions or concepts - Google Analytics, Adobe Analytics, Optimizely, Marketo, Pardot, Hubspot, Eloqua, targeting, personalization, analytics, etc, have completed Salesforce Trailhead training or if you're familiar with ticketing systems like Zendesk, Asana, or Jira.
  • Support Engineering Team Lead
    San Francisco, CA (or Remote, US Timezones)
    We are looking to add a team lead to our new Support Engineering team - someone who loves delighting customers as much as they like influencing product and finds excitement in being a part of building a cross-functional team from the ground up. Clearbit is a rapidly growing SaaS company (> 250% ARR last year) looking for talented and experienced B2B customer success folks to take us to the next level. We often compete (and win) against companies 10x our size, and we're looking to grow rapidly over the next year. We offer a highly collaborative environment with a very experienced team working on awesome cutting edge products. This is a new team - so it comes with a tremendous level of ownership and growth potential. If you enjoy cross-functionality, learning about MarTech and SalesTech, understanding customer challenges, working with the hottest startups and large enterprise companies, developing deep understandings about products, and being a true consultant for best practices, this is your role! Check out our Glassdoor Reviews
  • Become an internal and external go-to for our products and all sorts of Sales/Martech technology
  • Mentor your team around best practices, strategy, and new technology
  • Work with a diverse customer base on an ongoing basis, guiding, troubleshooting (sometimes in real time) and filing bugs as they arise, consulting customers of solutions and best practices
  • Review and document integrations in production
  • Strategize and implement with the team, constantly working toward building a world-class customer experience
  • Proactively help support customers as opportunities are identified, sometimes before the customer even knows!
  • 3 year experience in B2B SaaS Support
  • Proven experience working with top customers navigating challenging situations
  • Familiarity with Zendesk (automations, routing, guides, user permissions, etc) and working with SLAs
  • Familiarity in CRM, Analytics, Segmentation, or Personalization solutions
  • Experience mentoring junior support staff
  • Understanding of basic website development (html, css, js)
  • Experience working directly with customers and is driven by delivering exceptional customer experience
  • Comfortable in ambiguity and self sufficient in trying to find the solution
  • Problem-solving ability, customer centric outlook and excellent communication skill
  • Experience working with cross-functional teams (Sales, Marketing, Product)
  • Bonus Points if you're familiar with industry standard marketing and sales solutions or concepts - Google Analytics, Adobe Analytics, Optimizely, Marketo, Pardot, Hubspot, Eloqua, targeting, personalization, analytics, etc, have completed Salesforce Trailhead training or if you're familiar with ticketing systems like Zendesk, Asana, or Jira.
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